Fuel system of a handheld work apparatus

Abstract

The invention relates to a fuel system of a portable handheld work apparatus driven by an internal combustion engine. The fuel system includes a fuel tank ( 2 ), a fuel pump, a fuel line ( 4 ) leading from the fuel tank ( 2 ) to the fuel pump and a first suction head ( 5 ) which is disposed at an end ( 7 ) of the fuel line ( 4 ) at the fuel tank. At least a second suction head ( 6 ) is arranged within the fuel tank ( 2 ) and is connected in the fuel line ( 4 ) in series ahead of the first suction head ( 5 ). The second suction head ( 6 ) has an external suction surface which is formed by a porous covering ( 9 ). The porous covering ( 9 ) delimits a suction space. A guide is arranged in the suction space which guides the through-passing fuel flow at least approximately along the entire inner surface of the porous covering ( 9 ).

What is claimed is: 
     
       1. A fuel system for a portable handheld work apparatus driven by an internal combustion engine, the fuel system comprising:
 a fuel tank for holding fuel for operating said engine; 
 a fuel pump for pumping fuel from said fuel tank; 
 a fuel line leading from said fuel tank to said fuel pump and having an end at said fuel tank; 
 a first suction head mounted on said end of said fuel line; 
 a second suction head disposed in said fuel tank and connected into said fuel line in series ahead of said first suction head; 
 said second suction head having a porous covering defining an outer suction surface; 
 said porous covering having an inner surface delimiting a suction space within said second suction head for accommodating a fuel flow passing therethrough; and, 
 guide means mounted in said suction space for at least approximately guiding said fuel flow along said inner surface of said porous covering. 
 
     
     
       2. The fuel system of  claim 1 , wherein said second suction head has an end face, an inlet and an outlet formed on said end face; and, said guide means is configured as a partition wall extending from said end face into said suction space. 
     
     
       3. The fuel system of  claim 2 , wherein said porous covering extends in a longitudinal direction to have a length (L); said partition wall extends into said suction space to a depth (t); and, said depth (t) extends over at least 50% of said length (L). 
     
     
       4. The fuel system of  claim 3 , wherein said depth (t) extends over at least 75% of said length (L). 
     
     
       5. The fuel system of  claim 2 , wherein said inlet and said outlet define respective longitudinal axes which are parallel to each other. 
     
     
       6. The fuel system of  claim 2 , wherein said inlet and said outlet define respective longitudinal axes conjointly defining an angle (α) with respect to each other and wherein said angle (α) lies in a range of 45°≦α≦90°. 
     
     
       7. The fuel system of  claim 6 , wherein said angle (α) is approximately 60°. 
     
     
       8. The fuel system of  claim 2 , wherein said second suction head comprises a frame holding said porous covering therein; said inlet, said outlet and said partition wall are formed as a single piece to define a cover; and, said cover is connected to said frame. 
     
     
       9. The fuel system of  claim 8 , wherein said frame and said cover conjointly define an interface configured to permit said frame and said cover to be latched to each other. 
     
     
       10. The fuel system of  claim 1 , wherein said second suction head defines a peripheral direction; and, said porous covering is closed in said peripheral direction. 
     
     
       11. The fuel system of  claim 10 , wherein said porous covering is configured to be cylindrical. 
     
     
       12. The fuel system of  claim 1 , wherein said work apparatus has a usual work position for which there is an up direction and a lateral direction; said fuel tank having an elevation (h) in said up direction and a width (b) in said lateral direction; said elevation (h) is less than said width (b); said first suction head is disposed in a first half of said fuel tank referred to said lateral direction and said second suction head is arranged in a second half of said fuel tank. 
     
     
       13. The fuel system of  claim 12 , wherein said elevation (h) is less than half of said width (b). 
     
     
       14. The fuel system of  claim 1 , wherein said porous covering is defined by a sinter body. 
     
     
       15. The fuel system of  claim 1 , wherein said fuel pump is a membrane pump.